Issue with null characters in string returned by cpptrace exceptions

[dsafa]

Hello, I'm encountering issues with printing out the stack trace due to null characters being in the stack trace strings in the cpptrace exceptions. This is only really an issue because I am just catching the base std::exception and printing out exception::what() which causes the message to get cut off.

For example,

    try {
        throw cpptrace::logic_error("test");
    }
    catch (const std::exception& e) {
        std::cout << e.what() << std::endl;
    }

Results in output like this

Stack trace (most recent call first):
#0 0x

when the expected output should be like this

Stack trace (most recent call first):
#0 0x0007ff67ef1b4b00 in main() at...

I debugged it and I've narrowed it down to this format which eventually calls this Since the while loop won't necessarily iterate all n_digits times, the front of the number string is left alone with \0 values

Info OS: Windows 11 64bit Compiled with msvc

[jeremy-rifkin]

Thank you, that’s definitely a bug. I will investigate asap.

[jeremy-rifkin]

Was 0x0007ff67ef1b4b00 the actual value causing the improper format? It should always loop n_digits times and I tried to test that extensively but it's possible I missed something, or maybe it's too late at night to think about such things

[dsafa]

yeah I was pretty light on details. I've got an updated setup so I can give better details

setup I just got the latest branch and just built and ran it with visual studio as x64-debug.

I've modified the demo.cpp as this:

int main() {
    auto str = cpptrace::generate_trace().to_string();

    std::cout << str.c_str() << std::endl;
    std::cout << str << std::endl;
}

outputs:

Stack trace (most recent call first):
#0 0x
Stack trace (most recent call first):
#0 0x7ff745f7b487 in main() at C:\source\cpptrace-main\test\demo.cpp:36
#1 0x7ff745ff61f8 in invoke_main() at D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:78
#2 0x7ff745ff609d in __scrt_common_main_seh() at D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288
#3 0x7ff745ff5f5d in __scrt_common_main() at D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:330
#4 0x7ff745ff628d in mainCRTStartup(void*) at D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_main.cpp:16
#5 0x7ffc65b0257c in BaseThreadInitThunk
#6 0x7ffc67baaa47 in RtlUserThreadStart

Here are the actual values I observe in to_string

passed in: value | 140700007511175 | unsigned __int64 and n_digits | 16 | unsigned __int64

And during the iteration	i	value
15	140700007511175
14	8793750469448
13	549609404340
12	34350587771
11	2146911735
10	134181983
9	8386373
8	524148
7	32759
6	2047
5	127
4	7

Where the final string becomes "\0\0\0\07ff745f7b487"

and the stack trace:

>   demo.exe!microfmt::detail::to_string<4,15>(unsigned __int64 value, const char * digits) Line 99 C++
    demo.exe!microfmt::detail::to_string(unsigned __int64 value, const microfmt::detail::format_options & options) Line 107 C++
    demo.exe!microfmt::detail::format_value::write(std::string & out, const microfmt::detail::format_options & options) Line 183    C++
    demo.exe!microfmt::detail::format<4>(const char * fmt_begin, const char * fmt_end, std::array<microfmt::detail::format_value,4> args) Line 287  C++
    demo.exe!microfmt::format<char const * const &,unsigned __int64,unsigned __int64 const &,char const * const &>(const char * fmt, const char * const & <args_0>, unsigned __int64 && <args_1>, const unsigned __int64 & <args_2>, const char * const & <args_3>) Line 318    C++
    demo.exe!cpptrace::print_frame(std::basic_ostream<char,std::char_traits<char>> & stream, bool color, unsigned int frame_number_width, unsigned __int64 counter, const cpptrace::stacktrace_frame & frame) Line 169  C++
    demo.exe!cpptrace::stacktrace::print(std::basic_ostream<char,std::char_traits<char>> & stream, bool color, bool newline_at_end, const char * header) Line 203   C++
    demo.exe!cpptrace::stacktrace::to_string(bool color) Line 260   C++
    demo.exe!main() Line 36 C++

I hope that helps

[jeremy-rifkin]

Thank you so much, that’s fantastic. I really appreciate all the help to identify the issue. Knowing it is msvc and seeing n_digits incorrectly computed gives a pretty good idea of where the issue lies!

[jeremy-rifkin]

Thank you again so much, this is now resolved in main and I will release patch version soon

[dsafa]

thanks!